Formulations and Routes of Administration

Question 1

Define formulation

Answer 1

The form in which a pharmaceutical product is presented for therepeutic use (e.g. a tablet, cream, aerosol etc)

Question 2

Define ROA (route of administration)

Answer 2

The way by which a drug is delivered into the body
E.g. inhalation, oral, nasal, intravenous, ocular drug delivery, transdermal diffusion

Question 3

List the 3 factors that determine the most appropriate route of administration

Answer 3

1. Site of action.( for skin dermatitis an oral ROA won’t be approapriate.
2. Symptoms (oral ROA won’t be suitable for a patient who is vomiting or unconscious)
3. Technical/formulation capability

Question 4

A given route of administration can be used for local or systematic delivery, depending on the purpose of treatment.
E.g. Inhalation:
Local delivery: inhaled brochodilators for ashthma
Systematic delivery: inhaled insulin for diabetes

TRUE OR FALSE

Answer 4

TRUE

Question 5

Define oral ROA (enteral)

Answer 5

• Administration to or by way of the mouth
• Its the most common route of administration
• Formulation is swallowed into the GI tract –> absorption of drug

Question 6

Outline the pros of oral ROA

Answer 6

1. Non-invasive: No opening or incision of the body. Simply needs to be swallowed
2. Patient can self-administer
3. Simple and convenient (e.g. small - making them easy to carry around)
4. Low production costs because sterilisation is not needed

Question 7

Outline the cons of oral ROA

Answer 7

1. Slower onset of action: involves disintegration, dissolution and absorption. Tablet also needs to travel through the GI tract to reach the intestine – TIME LAG
2. **Drug degradation : digestive enzymes in GI tract and the high acid content can destroy the drug (e.g. of drug that is vulnerable to degradation is INSULIN)
   3. Vulnerable to first-pass metabolism in liver **
3. Not suitable for bitter or strong smelling drugs - aftertaste which does not feel nice - won’t adhere to the regimen - affects health outcomes
4. **Not suitable for unconscious or vomiting patients **

Question 8

What is a tablet?

Answer 8

A powder that contains the drug and excipient (e.g. diluents, binders, excipients) - compressed into a hard mass

Question 9

What are capsules?

Answer 9

Powder or liquid contained in a shell made from a polymer usually gelatin

Question 10

What is a syrup?

Answer 10

A solution containing a high concentration of sucrose or other sugars

Question 11

What is an elixir?

Answer 11

Flavoured/sweetened hydroalcoholic solution

Question 12

What are oral drops?

Answer 12

Solution, emulsion, or suspension administered in small volumes by a suitable device (e.g. dropper)

Question 13

How does the sublingual ROA work?

Answer 13

Formulation is administrated **beneath the tongue **. Available as sublingual tablets or sublingual sprays

Question 14

How does the buccal ROA work?

Answer 14

Buccal tablets are placed on the inside of the cheek or between the gum and lip

Question 15

Outline the pros for both sublingual and buccal ROA

Answer 15

1. Fast onset of action: high blood supply in the oral mucosa leads to rapid drug absorption
2. No first pass metabolism
3. Tablets can removed anytime in the event of adverse effects

Question 16

Outline the cons for both sublingual and buccal ROA

Answer 16

• Not suitable for bitter or strong smelling drugs
• High molecular weight drugs (e.g. proteins and peptides) cannot be absorbed

Question 17

How do parenteral (injections) ROA work?.

Answer 17

The **formulation is injected by the needle. **
A puncture needs to be made through the skin/blood vessel therefore formulation needs to be a liquid and sterile. Solids cannot be injected - vein can be blocked - stroke - death

Question 18

List the 4 main injection routes

Answer 18

1. Intravenous: within the veins
2. Intramuscular: within the muscles
3. Subcutaneous: beneath the skin
4. Intradermal: within the skin

Question 19

What determines the route of injection?

Answer 19

Angle and depth of needle.
1. An injection injected at a 90 degree angle - reaching the muscles - intramuscular
2. At a 45 degree angle - reaching subcutaneous tissue - subcutaneous
3. At a 25 degree angle - reaching the veins - intravenous
4. At 10-15 degrees - just puncturing into epidermis layer (which is the skin)

Question 20

The epidermis +dermis layer = skin. True or False

Answer 20

True

Question 21

List the pros of an Intravenous ROA

Answer 21

1. Directly delivers drug into systematic circulation - fast onset of action
2. Bioavailability is 100% - stronger therapeutic effect
3. No first pass metabolism
4. Suitable for unconcious or vomiting patients
5. Small (several ml; bolus) and large volumes (up to litres ) can be injected

Question 22

List the cons of an Intravenous ROA

Answer 22

1. Invasive and painful
2. Needs a qualified health-care professional to administer (e.g doctor or nurse) - sterilisation of area by alcohol to do injection
3. Risky - once drug is injected cannot be retrieved
4. Be very careful: intro. of air (bubble) or particulate matter may block the vein - stroke - death

Question 23

List the pros of Intramuscular Injections

Answer 23

1. Drug absorption is more predictable, less variable and more rapid compared to oral ROA due to blood vessels serving the muscles
2. Sustained release formulations can be used
3. No first pass metabolism

Question 24

List the cons of Intramuscular Injections

Answer 24

1. Invasive and Painful
2. Needs a qualified health-care professional to administer (e.g doctor or nurse)
3. Needs aseptic technique
4. Only small volumes (typically2-5ml) can be injected

Question 25

What is an intra-articular injection?

Answer 25

Injected within a joint

Question 26

What is an intra-spinal/intratheca injection?

Answer 26

Injected within a spine

Question 27

What is an intramedullary injection?

Answer 27

Injected within the marrow cavity of a bone

Question 28

Define Nasal ROA? List the formulations that can be administered into the nose

Answer 28

* Administration to or by way of the nose. * Can be used for local (e.g. nasal congestion) or systematic (migraines) Tx. * Available as nasal spray, nasal ointment or nasal powder

Question 29

What is the Inhalation ROA? List the formulations that can be administered to the lungs via mouth

Answer 29

* **Administered to the lungs by inhalation through mouth. ** * Can be used for local (bronchodilators to treath asthma) or systematic (inhaled insulin for diabetes) Tx. * Available as aerosols (e.g. dry powder inhaler, metered dose inhaler - puffer, soft mist inhaler, nebuliser)

Question 30

What is topical ROA? List common formulations

Answer 30

* **Administration to the skin. ** * Formulation is semi-solid usually for local Tx 1. creams (oil-in-water emulsion) 2. lotion (oil-in-water emulsion; more runny) 3. ointments (oily thick semisolid, no water) 4. Gel: suspension of small particles interpenetrated by a liquid; may contain a gelling agent to promote thickness 5. paste: semi-solids with high concentration of solids (20-50%) and stiff consistency

Question 31

What is the transdermal ROA?. list common form.

Answer 31

Administration through the skin to the systemic circulation by diffusion Available as transdermal patches (e.g. nicotine replacement therapy, opoid analgesics) - patches are applied to dry flat skin area (e.g upper arm, chest, back)

Question 32

Define ophthalmic ROA

Answer 32

* Drug is **administrated to the eye. ** * Used for local Tx (e.g. red eyes, eye infection) 1. Available as eye drops or eye ointment - Formulation must be produced sterile (note: can only be used for 28 days after opening due to the risk of microbial contamination)

Question 33

Define Auricular ROA

Answer 33

* Administration to the ear * Solutions or suspensions usually for local Tx (e.g. earwax removal, ear infection)

Question 34

Define Rectal ROA

Answer 34

1. Administration to or by the way of the rectum. Can be used for local (e.g. constipation, haemorrhoids) or systematic (e.g. fever or vomiting) Tx E.g. suppositories, liquid enema, creams, ointments , foam enema

Question 35

List the pros of rectal ROA

Answer 35

1. Suitable when oral route cannot be used - nausea+vomiting patients -Cannot swallow - GI problems - unconsious patients 2. Suitable for drugs that cannot be orally delivered - main reasons: drugs that cause adverse effects, have an unpleasant taste, prone to degradation in the GI tract

Question 36

List the cons of rectal ROA

Answer 36

1.Poor compliance, inconvenience 2. Absorption is slow & prone to high variability (e.g. presence of faeces) 3. Some drugs can cause local irritation of rectal mucosa, causes bowel evacuation

Question 37

Outline the vaginal ROA

Answer 37

* **Administration into the vagina** * Can be used for local Tx (vaginal infection, vaginal dryness due to menopause) * Formulations: vaginal creams and suppositories